executable tests for railroad diagrams

[dckc]

the railroad diagrams are not left-factored; I'm not even sure they're unambiguous. But I'd like to cook up a way to check them against all the monte files we have.

related work: bnf2turtle -- write a turtle version of an EBNF grammar

[dckc]

note recent related work:

https://git.io/vdYBZ
typhon/master 9dea711 Corbin: regex: Increasingly incorrect module name, and test.

[dckc]

I was using Masque to explore this thru Dec 2015 https://github.com/dckc/masque/tree/semantics 6b1c0ef

https://github.com/monte-language/spotter looks like a good way to resume. ocaml and haskell are not that different with regard to this work